Chair backrest



FIG. 1 is a perspective view of chair backrest showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left end view thereof;

FIG. 5 is a right end view thereof;

FIG. 6 is a top view thereof;

FIG. 7 is a bottom view thereof;

FIG. 8 is another perspective view thereof; and,

FIG. 9 is a perspective view thereof, shown with environmental subjectmatter.

The broken lines shown in the drawings are for the purpose ofillustrating environmental subject matter and form no part of theclaimed design.

CLAIM The ornamental design for a chair backrest, as shown anddescribed.